Since a touch panel embedded in a liquid crystal display device can be integrated with a color filter substrate (i.e. a color filter plate), the thickness of the whole touch display device is effectively reduced and the production process of the device is effectively simplified, thus such a device has been widely used. Generally, drive lines and sense lines used for a touch function are disposed at a side of the color filter substrate in an In-Cell touch panel, but it is difficult to disposed the drive lines and the sense lines used for the touch function at the side of the color filter substrate in a liquid crystal display device of a vertical drive electric field mode such as Twisted Nematic (TN), because a common electrode is disposed at the side of the color filter substrate. In order to achieve the built-in touch function of the liquid crystal display device of the TN mode, it has been proposed that the data lines and the gate lines at a side of an array substrate also function as the drive lines and the sense lines of the touch panel.
As illustrated in FIG. 1, the In-Cell touch panel 100 includes an array substrate 101, a color filter substrate 102, and a liquid crystal layer 103 sandwiched between the array substrate 101 and the color filter substrate 102. A number of data lines and gate lines are disposed on the array substrate 101, and the color filter substrate is connected with a timesharing Integrated Circuit (IC) 104. The data lines and the gate lines are respectively connected with the timesharing IC 104 through the color filter substrate 102. A frame scanning period of the timesharing IC 104 includes a touch period and a display period, the timesharing IC 104 sends touch drive signals to the data lines and the gate lines, and detects touch signals of the gate lines or the data lines at the same time during the touch period; and the timesharing IC 104 sends display signals to the data lines or the gate lines during the display period. Thus, the timesharing IC 104 not only provides the touch drive signals and the display signals, but also detects the touch signals, hence the load of the timesharing IC 104 is multiplied, and the timesharing IC 104 is unable to support such rapidly increased load especially in the case of a high resolution display device.
In addition, the data lines and the gate lines also function as the drive lines and the sense lines used for the touch function in the above technical solution, thus, for a mutual capacitor touch panel, the data lines and the gate lines are respectively used as plates for the mutual capacitor. However, due to the limited line widths of the data lines and the gate lines, the mutual capacitance of the touch panel caused by them is relatively small, and thus the sensitivity of the touch panel is seriously influenced.
In summary, the data lines and the gate lines also function as the drive lines and the sense lines of the In-Cell touch panel for the liquid crystal display device of a vertical drive electric field, where the In-Cell touch panel is demanding for the timesharing IC and causes the relatively small mutual capacitance of the touch panel, thus the development of such liquid crystal display device is seriously influenced.